Odontocheila microptera Moravec & Huber & Brzoska 2017

ODONTOcheila micrOPTera nom. nov.

(Figs 30–58)

Odontochila euryoides W. Horn, 1922: 100, 101, fig. 9, primary junior homonym of Odontocheila bennigseni euryoides W. Horn, 1906: 85 (currently a subspecies of Euryarthron bennigseni (W. Horn, 1897) – see “Remarks” below.

Type locality. “Brasilia”.

Odontocheila ? euryoides: Wiesner 1992: 80.

Odontocheila euryoides: Lorenz 1998a: 35.

Type material. Holotype [originally of O. euryoides] (by monotypy), ♂ in SDEI, labelled: “Brasilia / ex cab Dieck.” [handwritten] // “Coll. Ehlers / V. de Poll” [printed]; “ Type! / Dr. W. Horn” [printed] // “coll. W. Horn / DEI Eberswalde” [printed] // “ Holotypus ” [red, printed] // “ euryoides, mihi” [large green-blue collection label with black frame, handwritten] // “ Odontocheila euryoides W. Horn Type (DEI –Eberswalde) / borrowed by D. L. Pearson / 23.Oct.1996 (drawer # 60)”[printed] // “Revision Jiří Moravec 2012: / Holotype (by monotypy) / Odontochila / euryoides W. Horn, 1922 ” [red, printed] // “ Odontocheila / euryoides W. Horn, 1922 / det Jiří Moravec 2012” [printed]. The holotype is accompanied with separately mounted thoracic wing, labelled by Horn: “Unterflügel / von / Od. euryoides / m.” [handwritten].

Other material examined. Historical data. 1 ♀ in MFNB: “Hist. Coll. (Coleoptera), Nr. 3642, Odontocheila nitidicollis / Dej. / Bahia, Freireiss / Zool. Mus. Berlin”. 1 ♀ in BMNH: “Estancia San Noria / Rio San Javier, / Santa Fe, Argentine / G. E. Bryant / 12.I.1912 ”; “ Odontochila / nitidicollis / Dej. / Dr. W. Horn det, 1925”; “Pres. by / Imp. Bur. Ent. / Brit. Mus. / 1925–292”. All specimens labelled: “ Odontocheila / euryoides W. Horn, 1922), det Jiří Moravec 2012 (2014 respectively)” Recent data. 2 ♂♂, 10 ♀♀ in DBCN, 3 ♂♂, 1 ♀ in CCJM: “Uruguay / Hyw. 5, KM. 395 (N.- Tacuarembo) 179 m, -31.684, -55.926° / D. Brzoska 15-I-2017 ”. 2 ♂♂, 4 ♀♀ in JCDG: ibid., except for “leg. Johnnie Chong”. 4 ♂♂, 2 ♀♀ in DBCN: ibid. except for: “D. Brzoska 16-I-2017 ”. 8 ♂♂, 5 ♀♀ in JCDG: ibid., except for: “leg. Johnnie Chong”. 3 ♂♂ in DBCN: ibid., except for: “Hyw. 26, KM. 220 (W.- Tacuarembo) 164 m., -31.763, -56.077°, D. Brzoska 16-I- 017°”. 5 ♂♂, 2 ♀♀ in JCDG: ibid., except for “leg. Johnnie Chong”. 1 ♂, 1♀ in DBCN ibid., except for: “246 (W.- Tacuarembo) 171 m, 31.711, -55.866”. 2 ♂♂ in JCDG: ibid., except for: “leg. Johnnie Chong”.

Differential diagnosis. Odontocheila microptera nom. nov. shares the notably nitid, reddish-cupreous pronotal surface, immaculate elytra and coloration of other body portions with Odontocheila nitidicollis. However, O. microptera nom. nov. can be immediately distinguished by its uniquely mutually ovoid elytra in both sexes (Figs 30–36). Its male labrum is distinctly bicolored with large ivory-yellow anterior area (Figs 47–48) and has 4-dentate anterior margin which is truncate or shallowly emarginated in middle (lacking median tooth) with the anterolateral and anterior teeth in the same level, giving the male labrum almost transverse shape, in contrast to the predominantly black male labrum with 5-dentate anterior margin in O. nitidicollis. In contrast to the entirely black female labrum in O. nitidicollis, the female labrum in O. microptera nom. nov. is either entirely black or bicoloured and may resemble the bicoloured labrum in females of the species-group related to O. rutilans, including O. fulgens (but see annotation in the “Variability” below). Moreover, the terminal palpomeres of maxillary palpi are in O. microptera nom. nov. slightly but notably narrower (Figs 38–40, 42) than the almost spatulate-dilated terminal palpomeres in males of O. nitidicollis (Figs 10–12, 19), and also the antennal scape (Figs 20–21) is in O. nitidicollis slightly more dilated (but in both species never distinctly spatulate-dilated).

Because of its uniquely atrophic thoracic wings which are firmly connate with the soft thoracic tissue (Fig. 49), O. microptera nom. nov., is the only flightless species of Odontocheila; the total length of the atrophic wings (Figs 50–51) does not surpass the elytral third, in contrast to the normally developed, long wings in O. nitidicollis (Fig. 22).

The aedeagus apex (Figs 55–57) in O. microptera nom. nov. is a rather thick, dorsally directed hook, but the hook is on its ventral side rounded, thus more similar to the aedeagus apex of O. rutilans. Nevertheless, as in others of the species-group related to O. rutilans and O. fulgens (Klug, 1834), the shape in syntopic adults may vary, and in one male of O. microptera nom. nov. from Tacuarembo, Uruguay the aedeagus apex (Fig. 56) is somewhat similar to that in some of the aedeagi in O. nitidicollis. In turn, the aedeagus apex of the male of O. nitidicollis from Paraguayan Estancia Terrado (Fig. 28), as well as that from Bolivian Alta Vista (Fig. 29), is almost of the same shape as in most males of O. microptera nom. nov.

Redescription. Body (Figs 30–32) medium-sized (of a variable size independent of sex) 9.40–11.4 (HT 9.50) mm long, 2.90–3.80 (HT 3.20) mm wide, dark coppery or more vividly reddish-cupreous except for shiny reddishcupreous pronotum or also head, with faint green-blue lateral iridescence.

Head (Figs 10–12) shaped and coloured as in O. nitidicollis, width 2.80–3.35 mm.

Frons, vertex genae and clypeus coloured and with surface sculptures as in O. nitidicollis, but vertex usually less convex in middle, sometimes almost flat or with shallow anteromedian impression.

Labrum 4-setose, often strongly sexually dimorphic in coloration; male labrum (Figs 47–48) predominantly ivory-white (ochre-yellow in old specimens) except for narrow, black basolateral area, rather short, length 0.60– 0.75 mm, width 1.10–1.40 mm, basolateral and anterolateral teeth subacute or acute, anterior margin 4-dentate with anterolateral and anterior teeth in same level giving the labrum nearly transverse shape, truncate or shallowly emarginate in middle, lacking median tooth; female labrum (Figs 44–46) variably either entirely metallic black or with testaceous anteromedian or whole anterior area, but always with black basal area expanded to the middle, much longer, length 1.15–1.25 mm, width 1.40–1.50 mm, its tridentate median lobe with protruding median tooth of rather variable length.

Mandibles (Figs 37–41) shaped and coloured as in O. nitidicollis, but often paler (faded to brownish-testaceous in old specimens, such as in HT), and with similar variability in shape of inner teeth, but the third tooth is more often and also in left mandible notably smaller than the second and fourth (Fig. 41).

Palpi (Figs 38–40, 42) as in O. nitidicollis, but terminal palpomeres of maxillary in both sexes notably less distinctly dilated, width 0.15–0.17 mm.

Antennae (Figs 30–32, 37–39) shaped and coloured as in O. nitidicollis, but notably shorter, in male reaching only elytral third, in female only elytral shoulders, coloration in old specimens usually faded (antennomeres 3–4 in HT faded to pale mahogany with only apices metallic-black); scape moderately dilated, width up to 0. 28 mm.

Thorax. Pronotum (Figs 52–54) coloured and with surface sculpture as in O. nitidicollis, but the transverse rugae on pronotal disc are sometimes, particularly in male (also in HT) denser and more wavy; in male slightly longer than wide, length 2.00– 2.30 mm, width 1.90-2.15 mm, in female as long as wide or slightly wider, 2.20– 2.30 mm long, 2.20–2.40 mm wide.

Elytra (Figs 33–36) mutually notably ovoid, their outer margin markedly arched, length 5.70–7.00 mm, with widely arcuate humeri; anteapical angles widely arched towards apices which are in both sexes mostly almost acute with only small emargination towards distinct sutural spine; elytral surface punctate, but coloration slightly less variable and generally darker; whitish elytral maculation entirely absent.

Abdomen as in O. nitidicollis.

Legs as in O. nitidicollis, the black coloration in old specimens (HT) usually faded.

Aedeagus (Figs 55–57) moderately voluminous in middle, 3.10–3.50 mm long, 0.70–0.85 mm wide, with simply hooked apex which is ventrally rounded, rarely subquadrate (Fig. 56); internal sac as in O. nitidicollis and most other species of the species-group related to O. rutilans with large, normally shaped voluminous base of the flagellum (partly visible in Figs 55, 56).

Variability. Apart from that emphasized in the “Differential diagnosis” and the “Redescription” above, the most important is the variable coloration of the female labrum which is either entirely black, or distinctly bicoloured, thus similar to the bicoloured labrum in most females of O. fulgens. Although O. fulgens immediately differs by its whitish elytral maculation, it is important to rectify here the error by Rivalier (1969) who stated that one of the distinguishing characters of O. fulgens is metallic black female labrum, and such misleading error was adopted by Pearson et al. (1999). In fact, the labrum of the female holotype (MFNB) of O. fulgens is distinctly bicolored, as also are the labra of majority of the other examined females of O. fulgens from Argentina and Paraguay, except for females from Rio Salado, Argentina (IRSNB), where the female labrum is prevailingly metallic black with only testaceous median area which is often very narrow.

Etymology. The species name microptera = having small or rudimentary wings, is derived from ancient Greek.

Biology and distribution. This species was hitherto known (under the name O. euryoides) only from the holotype labelled “Brasilia”. Horn (1922, 1910, 1926) mentioned only Brazil as its occurrence. Only two other historical specimens were identified in collections within this revision of the genus by the first author: one of them the female (MFNB) from Bahia, Brazil, the other the female (BMNH) from the Estancia San Noria, Santa Fe, Argentina, both cited above. Although the female (BMNH) from Argentina was previously labelled by Horn as O. nitidicollis, he later (Horn 1928) mentioned a possible occurrence of this species (under O. euryoides) also in Argentina.

Therefore, the most surprising is that this flightless species was recently discovered by the third author and his collecting companion Johnnie Chong, in north-central Uruguay, in the three adjoining localities north of Tacuarembo (cited above), in a good number of 55 adults of both sexes. Nevertheless, it remains a great enigma how this flightless species could penetrate from the Atlantic Rainforest of north- and southeastern Brazil to the very distant country, as well as to Argentina.

The flightless adults run and hide in the vegetation and due to their atrophic thoracic wings, this species was obviously forced out of the vegetative cover. It is one of the few Odotocheila that can survive in Uruguay where probably most of the native forest has been removed and replaced with pine and Eucalyptus, as also in the area of the locality of O. microptera. The biotope is partly similar to that of O. nitidicollis, which is, however, a very good flyer, and therefore may occupy somewhat more various biotopes. Unlike most species of Odontocheila which usually occur along forest trails and more shaded areas, these two species inhabit more open and grassy areas, but O. microptera nom. nov. was mostly found in heavier grassy places. At one of the three Uruguayan localities with pine trees (Fig. 58), the adults were found among grass, but not under the trees; in the other two places they were found in heavy grassy areas along the shoulders of highways where no trees were present. It also may be significant that no other tiger beetle species was found in the habitats together with O. microptera nom. nov.

Remarks. Horn (1922) described Odontocheila euryoides despite the existence of Odontocheila bennigseni euryoides described previously by himself (Horn 1906) from Tanzania, and he kept this African taxon in the genus Odontocheila also later (Horn 1910, 1926) in his wide concept both of the subtribe Odontocheilina (as Odontochilina) and of the genus Odontocheila (as Odontochila) which in his sense also comprised some African and Asian taxa. Odontocheila bennigseni W. Horn, 1897 was first transferred to the African genus Euryarthron Guerin, 1849 by Rivalier (1957), but without mentioning its subspecies euryoides that was mentioned as a member of Euryarthron for the first time by Wiesner (1992).

Thus both O. bennigseni euryoides W. Horn, 1906 and its junior primary homonym O. euryoides W. Horn, 1922 were in use congeneric until 1992. The homonymy was overlooked also by Lorenz (1998a, b, 2005a. b).

According to Article 23.9.5 (ICZN 1999), when a species-group name in use is a junior primary homonym of another species-group name also in use, but the names apply to taxa not considered congeneric after 1899, the author must not automatically replace the junior homonym. However, in this case both homonyms were considered congeneric after 1899, so the junior name is permanently invalid (Article 57.2). Since there is no available synonym for Odontocheila euryoides W. Horn. 1922, the name must be replaced by a new substitute name (Article 60.3).